It is known to provide electrosurgical generators which provide different radio frequency (RF) power signals for cutting and coagulation, and also to switch between two different instruments, e.g. bipolar and monopolar instruments. In a first type of prior art system, it is also known to provide an electrosurgical instrument with a single electrode, and switching means on the instrument to connect the electrode alternately to either a cutting output or to a coagulating output from the generator. Examples of these types of instrument are to be seen in U.S. Pat. No. 4,427,006, U.S. Pat. No. 5,376,089 and U.S. Pat. No. 5,573,424.
Alternatively, in a second type of prior art system, it is known to provide an instrument with multiple electrodes, and to provide switching means on the instrument to be able to connect the power signal from the generator to different electrodes or combinations of electrodes. Examples of this type of instrument are to be seen in U.S. Pat. No. 5,269,780 and U.S. Pat. No. 5,951,551. The disadvantage of all of these prior art systems is that it is not possible to optimize both the signal supplied by the generator and the choice of electrodes. In the case of the first time of prior art system, the use of a single electrode means that its design must always be a compromise between designs suited to cutting and those suited to coagulation. In the case of the second type of prior art, the instrument uses the same output power signal from the generator for whichever combination of electrodes is deployed. U.S. Pat. No. 6,270,497 discloses a device which switches between coagulation and cutting operations, but which is relatively complicated in design.
It is an object of the present invention to provide an electrosurgical system which attempts to provide an optimized combination of electrodes in the handpiece and electrosurgical power signal from the generator, and which is relatively simple in operation.